Buckles are well known in the prior art. In an exemplary buckle of the prior art, for example, U.S. Pat. No. 6,711,790, a release button is used to urge the male or plug member to disengage from the female or socket member to achieve unlocking. In some other exemplary buckles of the prior art, for example, U.S. Pat. Nos. 5,709,014 and 6,543,101, such unlocking is achieved by subjecting an inclined plane of the release button to act on the inclined plane of the male or plug member so that the plug is disengaged from the locking position.
Regarding the restoration of the release button in existing prior art, some achieve the object by inserting the tongue of the male or plug member (see for example, U.S. Pat. Appln. No. 20050125970), some by means of the arm of the release button itself (see for example, U.S. Pat. No. 6,543,101), some by the integration of the release button on the female or socket member (see for example, U.S. Pat. No. 5,659,931), and some by the integration of the arm of the release button on the female or socket member (see for example, U.S. Pat. No. 6,170,133).
However, in the above-mentioned prior art, there exist problems such as unreliable, inconvenient in operation, and high manufacturing cost.